Remko Weijnen's Blog (Remko's Blog)

About Virtualization, VDI, SBC, Application Compatibility and anything else I feel like


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Red Gate .NET ReflectorI wanted to call a hash function from a .net executable from my code. My first step was to inspect the executable with Reflector.

The Hash function was in a namespace called Core:

Notice that the Core namespace is marked as internal so it was not meant to be callable outside of the executable. It’s still possible to call it using Reflection:

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  • Filed under: C#
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    After joining a new Windows 2008 R2 Server to the domain I could not login to the domain.

    I would get the following error message:

    The security database on the server does not have a computer acocunt for this workstation trust relationship.

    Additionally the following error was logged in the Eventlog:

    Event ID 3 | Error 1787 | Error Code 0x7 | KDC_ERR_S_PRINCIPAL_UNKNOWN | A Kerberos Message was received

     

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    imageI had to troubleshoot an application that was published with Citrix XenApp. The problem with this application was that it didn’t have an button/icon in the taskbar and the window would sometimes disappear.

    I noticed that this (cr)application was written in Visual Basic, so I decided to run it through a decompilation tool.

    The decompiler was able to list the forms used in the Application:

    image

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  • Filed under: Citrix, General
  • 2,960 views

    Nethood IconI am using a PowerShell script to copy some elements of from the users old profile location to a new location. This includes the Nethood ("My Network Places") folder which contains the Network Places shortcuts.

    A user reported that she could not save documents to Network Places anymore and after inspection the Network Places shortcuts were broken.

    I started comparing the old Nethood folder to the new and observed the following difference in Explorer:

    image

    When copying entries from the Nethood folder with Explorer manually they worked fine, so somehow Explorer gives the Nethood folder special treatment.

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    Today I was asked to troubleshoot an executable that didn’t work correctly on Windows XP Embedded.

    On startup it displayed the following message:

    I verified that System.Configuration.dll was present (in C:\Windows\Microsoft.NET\Framework\v2.0.50727).

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  • Filed under: General
  • 19,941 views

    Excel 2007 IconI was just browsing through the Options tab in Excel 2010 when I noticed the following setting:

    image

     

    This feature was introduced in Excel 2007.
    In the default settings, multi-threaded calculation is Enabled with "Use all processors on this computer".

    On a physical desktop this would be the preferred setting since it will make formula calculation as fast as possible.

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  • Filed under: General
  • 5,248 views

    This morning Arjan Beijer sent me an interesting link to a youtube video about obtaining the Citrix IMA Datastore password using Windbg.

    The video shows a method, discovered by Denis Gundarev to obtain the IMA Datastore password. Basically he uses DSMaint.exe and set’s a breakpoint on the call to CryptUnprotectData and then reads the password from memory.

    I tried to call the CryptUnprotectData API with the data read from the registry directly but this failed with error NTE_BAD_KEY_STATE, this is defined in winerror.h and it means “Key not valid for use in specified state”.

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    Just a small post today: a small commandline utility that reads the “DefaultPassword” LSA secret.

    This secret is stored in the registry under the SECURITY Hive:

    HKEY_LOCAL_MACHINE\SECURITY\Policy\Secrets\DefaultPassword

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    After figuring out how to encode and decode the Citrix passwords my next step for the upcoming Citrix Launcher is experiment with config.xml and authenticating to the Citrix Web Interface.

    imageI imported the NFuse.dtd from the Citrix Web Interface into Delphi with the XML Data Binding Wizard. The results in an NFuse Unit so I can easily create the XML data.

    To create an authentication packet I use the following code:

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  • Filed under: Citrix, Delphi
  • 11,625 views

    I am working on a launcher tool for Citrix XenApp that can not only connect to a published application or published desktop but can also leverage Citrix Workspace Control to reconnect to disconnected and/or active sessions.

    There doesn’t seem to be any sdk that exposed the data we need so I am trying to reproduce what the Citrix online plugi-in does.

    I used a HTTP monitoring tool to capture the traffic between the Online plug-in and the Web Interface. First the online plug-in will retrieve the config.xml from the server specified via the Change Server option:

    What is the address of the server hosting your published resources? | Server Address | Example: servername (for non-secure connections) | https://servername (for secure connections)

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  • Filed under: Citrix
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